Robotic Lawn Mower with Network Sensors

ABSTRACT

The smart robotic lawn mowing system utilizes the ultrasonic and RF sensors installing on the mower base and stands to define the mowing region, to track the position of the robotic lawn mower base, and to control and monitor the mowing routs. The installed sensors form a network for the system to determine the relative distances in between stands and robotic lawn mower base, and therefore the mowing is done with a controlled manner. The sensors are coupled together, and users, based on the application of the invention, can define the mowing sequences of the mowing zones, the areas of the mowing zones, and the mowing routes. The control of the mower may be wireless and users are able to monitor and modify the settings with a computer, a cell phone, and a tablet through wireless network, a wifi, and an internet.

This application is a Formal Application and claims priority to pending U.S. Patent application 61/574,866 filed on Aug. 11, 2011 by the same Application of this Application, the benefit of its filing date being hereby claimed under Title 35 of the United States Code.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a robotic lawn mower using network sensors to identify the mowing areas and zones, to define the mowing paths, and to program the mowing patterns. The invention utilizes ultrasonic, RF, and light sensors to define the mowing area and to track the position of the robotic lawn mower. The sensors are coupled together, and users, based on the application of the invention, can define the mowing sequences of the mowing zones, the areas of the mowing zones, and the mowing routes. The control of the mower may be wireless and users are able to monitor modify the settings with a computer, a cell phone, and a tablet through wireless network, a wifi, an internet.

2. Description of the Related Art

With the invention of the robotic lawn mower, people now can use it to do the lawn work and therefore save the time and energy for other things. A robotic lawn mower is an autonomous robot used to cut lawn grass. A typical robotic lawn mower requires the users to set up a wire at the lawn border to define the area to be mowed. The robot uses the wire to locate the boundary of the area to be trimmed, and in some applications, the robot can follow the wire back to the docking station for battery recharging. Robotic lawn mower can be quite sophisticated equipped with sensors to detect if there is a rain and to detect grass and non-grass area and some models can control the blade speed based on grass height and move in spiral pattern when longer grass is found.

However, the existing lawn mowers in the market, although with microcontroller or a CPU embedded on them, are still not flexible enough to allow users to freely use it at different lawns, to vary the mowing regions, to control the mowing paths, and to monitor the mowing situation locally or remotely. Such situations could be, for example, users may want to mow his or her house's lawn yard today, but tomorrow would like to help mow neighbor's lawn yard. The traditional method of setting up of the wire at neighbor's yard, if not impossible, would be very impractical. Another situation is that users may want to mow a specific region of lawn today and to mow another specific region of the lawn tomorrow, and may want to control the mowing sequence of the regions. For this need, a smart robotic lawn mower system which is able to define and to vary the mowing regions and to track the location of the mower during its operation is needed. Another application is that users may want to monitor and to modify the setting of mowing through a network or an internet. The invention here is to address these kinds of needs.

From the point of energy saving, a robotic lawn mower which is able to mow the lawn yard smartly is important. A smart mowing scheme is able to cover the entire lawn area but not to keep mowing the same spots repeatedly. The available existing robotic lawn mower in the market are not equipped with network sensors, and therefore, they may either repeat mowing some spots repeatedly or not be able to cover all the lawn area and some spots on the lawn are missed, and this is currently a common disadvantage of the available lawn mower products in the industry. The present invention, robotic lawn mower with network sensors, is able to control the mowing path and to avoid the repetition of the mowing. With network sensors, the robotic lawn mower is able to cover the spots that might be missed when using the traditional robotic lawn mower.

In this application, a smart robotic lawn mowing system allows users to freely use it at different lawns and at different regions in the lawn yard, is proposed. The core of the invention is to place the network sensors, such as the ultrasonic and RF sensors, in the lawn yard, and on the robotic lawn mower. The sensors in this application are referred as the network sensors because they are coupled together. The application is to install ultrasonic transmitter and RF receiver on the robotic lawn mower base, and to install ultrasonic receiver and RF transmitter on the stands. The stands here refer to the devices, not the robotic lawn mower base, allowing the ultrasonic and RF sensors to be put inside. The stands may be populated at the peripheral, inside, or outside of a lawn region. For practical applications, the stands may be a fence, a post, a solar light, a wood stick, or any other similar entities allowing the ultrasonic and RF sensors to be mounted on. The popular solar lamps, populating on the yards near the houses, are good locations for the installation of the sensors or stands. In general, the stands shall be flexible to be set up, and they shall be able to be put on or removed easily, and the portable stands make it easy to be moved to any different lawns or to different regions in the lawn yard. The ultrasonic transmitter on the robotic lawn mower is to transmit an ultrasonic wave toward the stands located at various locations, and the RF receiver on the robotic lawn mower is to receive the RF signals from the stands. The ultrasonic receivers on the stands are to receive the ultrasonic signals from the robotic lawn mower base, and after the receiving the ultrasonic wave from the mower, each stand will transmit a RF signal back to the robotic lawn mower base to notify the receiving of the RF.

With the network sensors, the robotic lawn mower system will firstly define the region to be mowed based on a simulation algorithm. After that, the robotic lawn mower base starts to mow the lawn yard, and the system will track the position of the robotic lawn mower base during its mowing operation. A mowing route and path is then either automatically programmed or picked and the robotic lawn mower base is then mowing the lawn yard with specified schemes. With this invention, the mowing route and pattern may be controlled, monitored, and modified by users.

SUMMARY OF THE INVENTION

The embodiment of the present invention provides a robotic lawn mowing system coupled with network sensors to control and to monitor the motion of the robotic lawn mower base.

In one embodiment, the robotic lawn mowing system contains a robotic lawn mower base and stands, and the stands are to accommodate ultrasonic receivers and RF transmitters.

In one embodiment, the robotic lawn mower base contains an ultrasonic transmitter and a RF receiver.

In one embodiment, the stand contains an ultrasonic receiver and a RF transmitter.

In one embodiment, the stands may be placed on the ground near the border of the mowing region, and at various spots to monitor the location of the robotic lawn mower base.

In one embodiment, the light sensors and Bluetooth devices may couple with the robotic lawn mower base and with the stands. For this case, the light sensors will replace RF sensors for the timing manners and signals transferring.

In one embodiment, the stands may be set up inside the mowing region, at the border of the lawn region, and at outside of the mowing region.

In one embodiment, the ultrasonic transmitter on the robotic lawn mower base is to transmit ultrasonic wave toward stands, ultrasonic receivers on the stands are to receive the ultrasonic waves from robotic lawn mower base, RF transmitters on the stands are to transmit RF signals toward robotic lawn mower base, RF receiver on the robotic lawn mower base is to receive RF signals from stands.

In one embodiment, the stands are used to define the mowing region and to track the position of the robotic lawn mower base at any time during its operation.

In one embodiment, the robotic lawn mower may be programmed to move around inside the lawn region to calculate the change of the relative distances among robotic lawn mower base and stands, to identify the positions of the stands, and to determine the boundary of the lawn yard.

In one embodiment, the robotic lawn mower may be programmed to mow the lawn yard without the repetition of the paths and to cover the lawn yard completely without missing spots.

In one embodiment, some stands may be fixed, floating, removable, and reusable.

In one embodiment, the network sensors may be using electromagnetic, sound, and light sources.

In one embodiment, the relative distances of the stands and robotic lawn mower base may be determined by the time-of-flight of ultrasonic waves.

In one embodiment, the stands are used to determine the boundary of the lawn yard.

In one embodiment, the stands may be coupled into several groups, and each group of stands may be used to control the rout of the robotic lawn mower base within a mowing zone.

In one embodiment, the lawn yard may be divided to several mowing zones with a program.

In one embodiment, the robotic lawn mower base may mow the lawn yard by a zone-by-zone scheme, and each zone may have different mowing patterns and paths.

In one embodiment, the groups of sensors may be at sleep mode.

In one embodiment, the sensor on the stands may be powered by solar cells, and may couple with solar lamps.

In one embodiment, the motion of the robotic lawn mower base may be monitored and control by a local or remote computer, a cell phone, or a tablet.

In one embodiment, a CPU or a microcontroller may be on the robotic lawn mower to do the calculation and simulation. The calculation is to determine the mowing region, to track the position of the robotic lawn mower base at any time during its operation, and to determine the mowing route, pattern, speed, frequency, and period.

In one embodiment, the robotic lawn mower base may have a memory device on it for the storage means, and a map of mowing region may be stored in the memory device.

In one embodiment, the sensors on the stands are to guide the motion of the robotic lawn mower base.

In one embodiment, a stand may be repeatedly used to define the border of the mowing region.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention may be obtained when the following detailed description is considered in conjunction with the following drawings, in which:

FIG. 1 illustrates a robotic lawn mower inside a lawn yard.

FIG. 2 illustrates a robotic lawn mower is located inside a lawn and the lawn may have several blocking regions.

FIG. 3 a illustrates several lawns separated by the blocking regions.

FIG. 3 b illustrates a lawn is divided into several regions.

FIG. 4 illustrates an uncontrolled mowing path of a robotic lawn mower inside a lawn.

FIG. 5 illustrates a robotic lawn mower inside a mowing region and several stands are placed on the ground near the border of the mowing region.

FIG. 6 a illustrates a robotic lawn mower is to transmit ultrasonic signals toward the stands, and the stands are to transmit the RF signals toward the robotic lawn mower.

FIG. 6 b illustrates a mechanism of the distance calculation from the ultrasonic and RF signals.

FIG. 7 illustrates a mechanism of the distance calculation from the ultrasonic and RF signals.

FIG. 8 illustrates an algorithm is used to calculate the relative distances of stands and robotic lawn mower, and to define the boundary of mowing area.

FIG. 9 illustrates sensor stands located at the lawn peripheral to define the boundary.

FIG. 10 illustrates stands located at the lawn peripheral to define the boundary of lawn yard.

FIG. 11 illustrates floating stands are used to define the boundary of the lawn yard.

FIG. 12 illustrates stands located at the lawn peripheral to define the boundary of the lawn yard.

FIG. 13 illustrates a lawn yard may be divided into several mowing zones with a program.

FIG. 14 a illustrates stands may be located inside the lawn area but at outer boundary of the blocking region.

FIG. 14 b illustrates stands may be located inside the lawn area but at outer boundary of the blocking region, and the lawn area may be divided into several zones in the mowing program.

FIG. 14 c illustrates that the robotic lawn mower may do the mowing by a zone-by-zone scheme.

FIG. 14 d illustrates that the robotic lawn mower may do the mowing by a zone-by-zone scheme.

FIG. 15 illustrates that the mowing zones may have different mowing patterns, and each zone may have different mowing settings.

FIG. 16 a illustrates the stand includes an ultrasonic receiver, a RF transmitter, a battery, and a solar cell, and the stands may be at sleep mode if not in operation.

FIG. 16 b illustrates the groups of sensors may be at sleep mode or activation mode.

FIG. 16 c illustrates an electromagnetic signal, a light signal source, and a sound wave may be used to determine the relative distances of the robotic lawn mower base and the stands.

FIG. 17 illustrates that the robotic lawn mower base may do the mowing zone by zone.

FIG. 18 illustrates that the mowing from the robotic lawn mower may be controlled and monitor with a computer, a cell phone, a table, at either local or remote site.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Furthermore, note that the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not a mandatory sense (i.e., must). The term “include”, and derivations thereof, mean “including, but not limited to”. The term “coupled” means “directly or indirectly connected”.

DETAILED DESCRIPTION OF THE INVENTION

The invention generally relates to a robotic lawn mower base 1 coupled with network sensors, allows users to freely use it for different lawns and at different regions in the lawn. The mowing path may be controlled and monitored with the network sensors. The system will firstly determine the mowing region, such as the size and the position of the border enclosing the lawn. Secondly, after the determination of the border of the lawn, the robotic lawn mower base 1 will be ready to mow and a tracking method is used to track the position of the robotic lawn mower base inside the mowing region at any time during its operation. Thirdly, after knowing the lawn size and border position, and the mower's position is tracked at any time during its operation, either a microcontroller or a CPU on the mower will determine the mowing route and patterns. With this invention, the determined mowing path will define a route to avoid the repetition of mowing the same spots. Furthermore, a lawn yard may be divided into several zones with a program, and the robotic lawn mower base 1 may mow the lawn zone by zone, and the mowing may be monitored by a computer or a cell phone through a local or remote network. With the invention here, users utilize the system for their lawn, their neighbor's lawn, or any other different lawns at different places. Furthermore, the system allows the users to vary their mowing region and routs depending on their needs and preference.

The advantages of the robotic lawn mower 1 are explained in detail in the text and with figures below. FIG. 1 illustrates a typical application of a robotic lawn mower base 1. The robotic lawn mower base 1 is to mow a region 10 enclosed by its outer boundary 11 at a land 100. An important operation of the mower is not to travel outside of its outer boundary 11. For this regard, the existing robotic lawn mower 1, in the market right now, will set up a wire beneath the ground at the lawn's outer border, to constrain the motion of the mower. When the robotic lawn mower 1 gets close to the wire, it will sense the electromagnetic wave from the wire and therefore change its mowing directions. The drawback of the wire is that a pre-installation of the wire will be required and it will be extremely difficult to use the robotic lawn mower 1 for neighbor's lawn. Furthermore, users may like to vary their mowing regions depending on grass condition or whatever any other personal preference. The available lawn mowers in the market right now do not provide this kind of flexibility and therefore the current application is to address these needs.

FIG. 2 illustrates one example of the robotic lawn mower base 1 to mow a region with several objects inside. The objects could be a bush of flowers, a swimming pool, a tree, and other things. The robotic lawn mower base 1 is not allowed to go across these objects. In this application, these objects are defined as “blocking region” 12 here. The dashed line in the figure illustrates a possible way of setting up the wire so the robotic lawn mower 1 will not go across the border and get into the blocking regions 12. In one embodiment, the wire is difficult to install for such a complex geometry, and people may prefer not to dig the lawn yard. In another embodiment, people may not want to mow the entire region in one shot, and may want to divide the region into several mowing zones, and do the mowing of each zone at the time of their convenience. Therefore, a flexible robotic system will be needed for this kind of situation.

FIG. 3 a illustrates a possible situation that the lawn regions 10 to be mowed could be separated from each other and are not connected together. The regions may be separated from each other by a bush of flower, a concrete road, a swimming pool, or some tress. For the situation, it will be very difficult to set up the wires on each region's border, and a flexible robotic lawn mower 1 will be preferred. Another situation is that people may want to mow different lawns at totally different locations, and the lawn may have various geometries, and therefore, it will be not practical to use the wires for such situation. The installation of the electric wires for a gardener who wishes to use robotic lawn mower 1 for his many customers seems if not impossible will be a very tedious work.

FIG. 3 b illustrates, in one situation, users may want to mow different zones of a lawn yard at different time even the zones are connected together, and may prefer to mow some zones more frequently than the other zones. The dash lines in the figure represent the boundaries of the zones. In one embodiment, the zones may be overlapped, or connected, or disconnected.

In summary for the stated situations above, a smart robotic lawn mower 1 may be needed. The smart robotic lawn mower 1 system allows the users to freely define their owing regions, and user may carry the system to anywhere without the need to set up the electrical wires. The application may be very useful for a gardener who has many customers and like to mow different lawn yards at the same time.

FIG. 4 a and FIG. 4 b illustrate typical mowing paths for a robotic lawn mower base 1 without network sensors system. The path may be in random pattern, or even with an assigned program, the mower may repeat the mowing at some spots or not be able to cover the entire lawn area. The repetition of the mowing spots, as shown in FIG. 4 a, will be wasting the electricity and it may take much longer time to finish the yard work, and this is the an issue for the available robotic lawn mower 1 in the market now. For the lawn yard which has several blocking regions 12 inside it, such as shown in FIG. 4 b, the situation becomes more complicated and may be difficult for mowers without network sensors to cover entire lawn area because mower does not have visions to look at the yard situation. This invention, with network sensors provides a solution for robotic lawn mower 1 to detect outer boundary of the lawn yard and internal blocking regions. An efficient mowing path, without the repetition of mowing and be able to cover entire lawn area, is then constructed.

FIG. 5 illustrates the concept of the smart robotic lawn mower base 1 with network sensors. The system contains one or more robotic lawn mower base 1. The robotic lawn mower base 1 is to be doing the yard work inside a region of the lawn yard 10, and the dashed line in the figure represents the boundary of the lawn yard. The region's geometry and size could be different. To define the mowing region, some sensors will be needed. In this application, the sensors are to be put inside the stands, and these stands are to be put at the outer border or the peripheral of the lawn, as shown in the figure. Before the usage of the smart robotic lawn mower 1 system, the stands may be placed on the ground at the border of the lawn. In one embodiment, the more number of stands may be better to capture the geometry of the mowing region. However, if the geometry is quite simple, then there is no need to put lots of stands. For a square lawn region, four of stands may be enough to depict the mowing area. For a lawn region having curves or irregular shapes at the border, more stands may be needed for the robotic lawn mower base 1 to identify the mowing region.

FIG. 6 a illustrates that the robotic lawn mower base 1 is transmitting ultrasonic wave toward the stands, and the stands 2 are transmitting RF signals toward robotic lawn mower base 1. The robotic lawn mower base 1 device may be designed to transmit the ultrasonic waves in 360 degrees or in specified angles, and the device may comprises several ultrasonic transmitters to take care of different directions and angles. Ideally all the ultrasonic transmitters shall transmit the sound waves at the same time, but since the sound is traveling at a very high speed, therefore a small time delay to transmit the sound waves among transmitters, is still workable as long as the timing is carefully calibrated. The purpose of the design is to determine the relative positions and distances in between the robotic lawn mower base 1 and the stands 2. FIG. 6 b illustrates the mechanism for determining the relative distances. The robotic lawn mower base 1 is equipped with an ultrasonic transmitter and a RF receiver. As the robotic lawn mower 1 transmits an ultrasonic sound wave out, the sound wave takes time to reach each stand, and the relative distance, as shown in the figure, can be calculated based on the time-of-flight because the sound speed is basically a known value although the value has to be calibrated base on the environmental temperature and humidity. The stand is equipped with an ultrasonic wave receiver and a RF signal emitter. Upon the receiving of the ultrasonic wave, the stand may transmit a RF signal back to notify the robotic lawn mower base 1. In theory, the RF signal takes time to travel back to robotic lawn mower base 1, but because the RF signal will travel at near light speed, therefore the time-of-flight of RF signal is very small and hence may be ignored. In practical applications, the operation of the electronic circuits on both the robotic lawn mower base 1 and on the stands may have electronic latency time delay, and all of these delays shall be considered in order to obtain accurate time-of-flight to calculate the relative distances.

In one embodiment, the RF signals may be used to calibrate and to synchronize the timing on the robotic lawn mower base 1 and on the stands. One example is that, right before or right after the robotic lawn mower base 1 transmitting an ultrasonic wave out toward all stands, the mower base may transmit a RF toward all stands, and in theory, all the stands shall receive the RF signal at the same time and all the stands may define this particular time flag as a reference. Each stand, after upon the receiving of the coming ultrasonic wave from the mower base, may calculate the time difference in receiving ultrasonic and RF signals, and therefore able to calculate how far its distance away from the mower base. In one embodiment, each stand may have a particular address or an ID so the robotic lawn mower base 1 knows where is RF signal coming from. The address or ID of the stands may be achieved by either hardware or software. By knowing exactly each of the RF signal comes from which stand will determine the exact relative distances between robotic lawn mower base 1 and the stands 2. In one embodiment, the RF signal may be replaced with for example a light signal, or an electromagnetic signal. One example is to use infrared light signal, and each infrared signal may have particular wave length or frequency or ID so the robotic lawn mower 1 may identify where is the signal source coming from.

FIG. 7 a illustrates that the relative distances, such as, d1, d2, and d3, between stands and robotic lawn mower base 1 can be calculated based on the time-of-flight, but the relative distances among stands are not known and therefore the boundary of lawn yard may not be determined completely. One solution is to have one of the stands to transmit ultrasonic wave toward other stands, and to receive RF signals from other stands, and FIG. 7 b illustrates the approach. In one embodiment, more than one of stands may have the ultrasonic transmitters in order to better define the lawn yard boundary. In another embodiment, the stands may be extruded out of ground to form a 3D configuration, and the relative distances will be calculated based on 3D trigonometry. In one embodiment, there may be no need to equip the ultrasonic transmitters on the stands, as shown in the FIG. 8. Initially the robotic lawn mower 1 may be located at position P1, and all the relative distances between stands 2 and robotic lawn mower base 1 can be calculated based on time-of-flight of ultrasonic waves. The next step is that the robotic lawn mower 1 is programmed to move a distance L1 to the position P2, and again the relative distances between the stands and robotic lawn mower 1 are calculated. The change of relative distances will be used to identify the locations of the stands. In one embodiment, the robotic lawn mower base 1 may be programmed to travel several positions, such as P3, P4 . . . to calculate the changes of the relative distances between the stands and robotic lawn mower base 1. The step may be used to eliminate the uncertainties and numerical errors, and to confirm the accuracy of the geometry of the lawn yard. The positions of P1, P2, P3, . . . may be flexibly chosen by a computational algorithm to determine relative distances. In one embodiment, the approach used here will be able to save electricity because transmitting the ultrasonic signals from several stands may consume more electricity power.

If the geometry of the lawn yard is complicated, more stands may be needed to define the boundary of the lawn yard and FIG. 9 illustrate one example. However, using lots of stands may increase the cost and the power consumption. In one embodiment, after the definition of the lawn yard boundary, most of the stands may be removed as shown in FIG. 10, and only a few fixed stands stay. In the figure, the motion of the robotic lawn mower 1 is tracked by three stands. The relative distances between three stands and robotic lawn mower base 1 is to track the position of the robotic lawn mower base 1 at any time during its operation. In a further embodiment, two or more than two stands 2 may be used to track the positions of the robotic lawn mower base 1 during its operation.

For a lawn yard with complicated geometry such as several curves at its boundary, as shown in FIG. 11, more sensors, and therefore more stands, may be needed. The increasing number of stands may be more difficult to maintain, and the cost may be increased. In one embodiment, some stands may be fixed and not be moved, such as the sensors A, E, and H, as shown in the figure. These stands will function as the referencing positions, which mean that either the robotic lawn mower base 1 or other stands may use these referencing positions to identify their own positions. In another embodiment, some stands may be floating which means that they may be used more than once and they may be removed. With the known positions of referencing stands, the floating stands may be used to identify a portion of the lawn yard boundary, and after the positions are determined, the positions will be recorded for example on the CPU or microcontroller on the robotic lawn mower base 1, or on a computer. Since these floating stands' positions are recorded and known, these stands may be removed and be reused for other places, such as another portion of the lawn yard boundary. The floating and the removable stands may be useful when the geometry of the lawn yard is complicated or large.

FIG. 12 a illustrate the stands are located at the lawn yard boundary, and FIG. 12 b illustrates four stands are used to track the position of the robotic lawn mower base 1. In one embodiment, the stands used to track the position of the robotic lawn mower 1 may be designed to be at arbitrary locations, either inside or outside the lawn yard, and either on the boundary or not on the boundary of the lawn yard, as shown in FIG. 12C. In real applications, the selection of the sensors may need to consider how well the ultrasonic signals to be clearly transmitted and received.

In one embodiment, a lawn yard may be divided into several mowing zones as shown in FIG. 13. When a lawn yard is too big or the yard shape is very irregular, the division of one single mowing zone to several mowing zones will be very useful for the users to control and to monitor the robotic lawn mower base 1. In one embodiment, the zones may be overlapped, connected, or disconnected, and each mowing zone may have its own stands to track the position of the robotic lawn mower base 1. The application may be useful when users like to mow different zones at different time in a day or different date in a week. In one embodiment, the stands may be used for more than two zones, for example, a stand which is sitting near two neighboring zones may be used for both two zones. In one embodiment, a stand may be used for several zones.

FIG. 14 a illustrates that the stands may be at the boundary of the lawn yard and be at the boundary of the blocking region. The CPU or microcontroller on the robotic lawn mower 1 may be programmed to identify what sensors are at the interior boundary of the blocking region. FIG. 14 b illustrates that a complicated geometry of the lawn yard, which has blocking region inside it, may be divided into several mowing zones with a program. FIG. 14 c illustrates that a lawn yard which has many blocking regions may be divided to several zones with a program, and the robotic lawn mower 1 may be programmed to do the yard work zone by zone following a sequence. FIG. 14 d illustrates that when the lawn yard geometry is big and long and irregular, then users can program the mowing sequence.

The central core of the invention is that the stands are able to detect and to define the boundary of the mowing zones. After the identification of the mowing boundary, a mowing pattern is to be constructed for the robotic lawn mower 1 to do the yard work. In one embodiment, the mowing pattern may be constructed based on any numerical schemes, and FIG. 15 illustrates one example of a lawn yard divided into several mowing zones, and different mowing patterns are applied at the zones. The mowing patterns may be defined by practical concerns, such as, a zone where the grass grows very fast then the robotic lawn mower 1 may be programmed to mow the zone repeatedly and the paths may be repeated, a zone where the grass grows very slow then the robotic lawn mower 1 may mow it once every other days. The mowing patterns may be programmed according to users' preference, such as, users may prefer to mow a zone with offset and parallel lines, a zone with spiral and raster paths, and so on. From the points of economics, in general, people may prefer not to overlap the paths to save battery power and therefore lower their electricity bill, and this invention provides an excellent solution.

FIG. 16 a illustrates that a stand 2 may include a RF transmitter 23, a battery 22, and an ultrasonic receiver 21. In one embodiment, a solar cell 20 may be added on it to power the rechargeable battery 22 automatically. An electrically self-rechargeable stand is easy to maintain without the attention from the users. The transmitter and receiver may couple with for example a solar lamps which are commonly used at the front or back yard of the house, at the two sides of the drive way, and at various locations. In general, the locations of network sensors may be at the similar spots as the solar lamps, and the increasing popularity of garden solar map makes the use of robotic lawn mower 1 with network sensors easy to be implemented because the installation of the network sensors is just as straightforward as the garden solar lamps. In one embodiment, the sensors may be at their sleep mode while the robotic lawn mower 1 is not doing the yard work or while the sensors are not activated or awaked by the robotic lawn mower 1. The sleep mode of the RF wireless sensor may be programmed as ZigBee technology. In one embodiment, the stands where the ultrasonic and RF sensor are put on may be programmed to be at sleep mode as well. FIG. 16 b illustrates that the stands may have several groups, and each group may be working independently hence while a group of stands are working, the other groups of stands may be at their sleep modes to save the electricity. FIG. 16 c illustrates that, instead of using RF transmitter, a light source emitter 24, such as infrared, may be used. For this application, an infrared light receiver is on the robotic lawn mower base, and an infrared light transmitter is on the stand. On the stand 2, when it receives the ultrasonic wave signal from the robotic lawn mower base 1, a light signal may be sent back to the robotic lawn mower base and the relative distance between stand 2 and mower base can be calculated. In one embodiment, an electromagnetic wave, a light source, and a sound wave may be used as the network sensors.

FIG. 17 illustrates a lawn yard may be divided into three mowing zones, namely, 1, 2, 3, and each mowing zone may have a group of stands, which are group A, B, and C here, to track the motion of the robotic lawn mower base 1 inside each zone. One application is that a robotic lawn mower base 1 starts from its docking station to enter into the zone 1 with the guidance of the stands from group A. The robotic lawn mower 1 will do the yard work at zone 1, and after the finishing of the yard work in the zone, it will move into zone 2 with the guidance of the stands from group B, and after finishing the yard work at zone 2, it will move into zone 3 with the guidance of the stands from group C. In one embodiment, the motion of the robotic lawn mower base 1 may be controlled with a zone-by-zone scheme, and robotic lawn mower base 1, at different zones, may have different mowing conditions, such as, mowing time, mowing patterns, mowing frequency, mowing path, and so on. In one embodiment, the groups of stands may be at sleep mode or at activation mode depending on the location of the robotic lawn mower base 1, and the robotic lawn mower base 1 may be able to advise the groups of stands to be at sleep mode to save electricity. In one embodiment, all groups of stands may be at sleep mode in the beginning, or while robotic lawn mower 1 is at its docking station. Furthermore, in one embodiment, the group of stands may be awaked only when they are being advised by the mower base.

FIG. 18 illustrates that the mowing path could be controlled and monitored by a computer, a cell phone, and a tablet. The controlling and monitoring may be through a local or a remote network. The communication may be through an internet, a WiFi, and a 3G or 4G network. 

1. An apparatus for mowing the lawn yard, comprising a robotic lawn mower base, an ultrasonic device, and a RF device built on the stands and robotic lawn mower base, to allow users to define the mowing regions, to track the position of robotic lawn mower base, and to program the mowing routes and paths;
 2. The robotic lawn mower base of claim 1, comprising a plurality of ultrasonic transmitter devices to transmit ultrasonic waves toward the stands, and a RF receiver device to receive the RF signals from the stands;
 3. The ultrasonic transmitter devices of claim 2, comprising a mean to transmit ultrasonic waves toward different directions to the said stands, each said stand upon the receiving of the ultrasonic wave is to calculate the time-of-flight and therefore its relative distance to the said robotic lawn more base;
 4. The stands of claim 1, comprising an ultrasonic receiver device and a RF transmitter device, the ultrasonic receiver is to receive the ultrasonic wave from the robotic lawn mower base, the RF transmitter device is to transmit a RF signal toward the robotic lawn mower base, and the stands are to be populated on the ground;
 5. The ultrasonic and RF devices of claim 1, on the said robotic lawn mower base and on the said stands, comprising means for measuring the time-of-flights of ultrasonic sound waves and the relative distances among said robotic lawn mower base and said stands, for determining the border of the yard lawn region, and for the tracking of the position of said robotic lawn mower;
 6. The ultrasonic and RF devices of claim 1, are coupled together to comprise a mean to determine the time-of-flight and relative distance in between said stand and said robotic lawn mower base, the RF is used to define a time flag on the said stand, to transfer the information in between said stand and said robotic lawn mower;
 7. The RF devices of claim 1, on the said robotic lawn mower and said stands, comprising means to synchronize the timing of the parts of the mowing system, to calibrate the time flags of the parts mowing system, and therefore to determine the relative distances among said robotic lawn mower base and said stands;
 8. The robotic lawn mower base of claim 1, comprising means to determine the relative locations of said stands, by moving itself inside the lawn yard, and to determine the relative distances among the said robotic lawn mower base and said stands, based on the Triangulation;
 9. The stands of claim 1, comprising a solar cell and a battery to provide the electricity needed for the operation of the said RF and said ultrasonic devices, and the said stands may couple with the applications of solar lights, and the stands may be in sleep mode while the said robotic lawn mower base is not doing the mowing work;
 10. The stands of claim 1, comprising means to be fixed and floating at various locations to determine the border of the lawn yard, to determine the location of the said robotic lawn mower base, to define the mowing zones and areas, to identify the objects inside the lawn yard, to define the sequence of mowing of lawn zones, and to define the mowing patterns of the zones;
 11. The mowing apparatus of claim 1, comprising means to control and to monitor the position of said robotic lawn mower base inside the lawn region, with wire and wirelessly connections, with local and remote communications, with internet and WIFI, with a gadget selected from the group consisting of a desktop computer, a cell phone, a tablet, a notebook computer, and a handheld mobile device;
 12. The stands of claim 1, comprising means to define their addresses and IDs while transferring their RF signals toward the said robotic lawn mower base, with the methods consisting of a hardware and software approaches, and therefore to determine each relative distance in between each said stand and said robotic lawn mower base;
 13. An apparatus for mowing the lawn yard, comprising a robotic lawn mower base, a light device, and an ultrasonic device; whereas the light devices are to transmit and receive light signals, to couple with ultrasonic device, to determine the relative locations of the said robotic lawn mower base and said stands, such that the grass on the lawn yard can be mowed with a controlled manner. 